They were escorted from the International Maritime Boundary line by the Indian Coast Guard.
Priest Michael Raj said hundreds of fishermen from Sri Lanka also attended the festival.
The pilgrims who returned today were checked by police and customs officials before they were allowed out of the harbour.
Though India ceded Katchatheevu to Sri Lanka through treaties in 1974 and 1976, pilgrims from the country are allowed to take part in the annual festival of St Antony's Church in the islet.